thunderbolt: Add CL1 support for USB4 and Titan Ridge routers

In this patch we add support for a second low power state of the link: CL1.
Low power states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle.
We enable it, if both sides of the link support it,
and only for the first hop router (i.e. the first device that connected
to the host router). This is needed for better thermal management.

Signed-off-by: Gil Fine <gil.fine@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 40 insertions, 15 deletions

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 8ab3530dfa0d..8e9fdc4e0650 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -215,7 +215,7 @@ static int tb_enable_tmu(struct tb_switch *sw)
 	int ret;
 
 	/* If it is already enabled in correct mode, don't touch it */
-	if (tb_switch_tmu_hifi_is_enabled(sw, sw->tmu.unidirectional_request))
+	if (tb_switch_tmu_is_enabled(sw, sw->tmu.unidirectional_request))
 		return 0;
 
 	ret = tb_switch_tmu_disable(sw);
@@ -664,13 +664,24 @@ static void tb_scan_port(struct tb_port *port)
 	tb_switch_lane_bonding_enable(sw);
 	/* Set the link configured */
 	tb_switch_configure_link(sw);
-	/* Silently ignore CLx enabling in case CLx is not supported */
-	ret = tb_switch_enable_clx(sw, TB_CL0S);
+	/*
+	 * CL0s and CL1 are enabled and supported together.
+	 * Silently ignore CLx enabling in case CLx is not supported.
+	 */
+	ret = tb_switch_enable_clx(sw, TB_CL1);
 	if (ret && ret != -EOPNOTSUPP)
-		tb_sw_warn(sw, "failed to enable CLx on upstream port\n");
+		tb_sw_warn(sw, "failed to enable %s on upstream port\n",
+			   tb_switch_clx_name(TB_CL1));
 
-	tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI,
-				tb_switch_is_clx_enabled(sw));
+	if (tb_switch_is_clx_enabled(sw, TB_CL1))
+		/*
+		 * To support highest CLx state, we set router's TMU to
+		 * Normal-Uni mode.
+		 */
+		tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_NORMAL, true);
+	else
+		/* If CLx disabled, configure router's TMU to HiFi-Bidir mode*/
+		tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI, false);
 
 	if (tb_enable_tmu(sw))
 		tb_sw_warn(sw, "failed to enable TMU\n");
@@ -1410,7 +1421,12 @@ static int tb_start(struct tb *tb)
 		return ret;
 	}
 
-	tb_switch_tmu_configure(tb->root_switch, TB_SWITCH_TMU_RATE_HIFI, false);
+	/*
+	 * To support highest CLx state, we set host router's TMU to
+	 * Normal mode.
+	 */
+	tb_switch_tmu_configure(tb->root_switch, TB_SWITCH_TMU_RATE_NORMAL,
+				false);
 	/* Enable TMU if it is off */
 	tb_switch_tmu_enable(tb->root_switch);
 	/* Full scan to discover devices added before the driver was loaded. */
@@ -1455,16 +1471,25 @@ static void tb_restore_children(struct tb_switch *sw)
 	if (sw->is_unplugged)
 		return;
 
-	/* Silently ignore CLx re-enabling in case CLx is not supported */
-	ret = tb_switch_enable_clx(sw, TB_CL0S);
-	if (ret && ret != -EOPNOTSUPP)
-		tb_sw_warn(sw, "failed to re-enable CLx on upstream port\n");
-
 	/*
-	 * tb_switch_tmu_configure() was already called when the switch was
-	 * added before entering system sleep or runtime suspend,
-	 * so no need to call it again before enabling TMU.
+	 * CL0s and CL1 are enabled and supported together.
+	 * Silently ignore CLx re-enabling in case CLx is not supported.
 	 */
+	ret = tb_switch_enable_clx(sw, TB_CL1);
+	if (ret && ret != -EOPNOTSUPP)
+		tb_sw_warn(sw, "failed to re-enable %s on upstream port\n",
+			   tb_switch_clx_name(TB_CL1));
+
+	if (tb_switch_is_clx_enabled(sw, TB_CL1))
+		/*
+		 * To support highest CLx state, we set router's TMU to
+		 * Normal-Uni mode.
+		 */
+		tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_NORMAL, true);
+	else
+		/* If CLx disabled, configure router's TMU to HiFi-Bidir mode*/
+		tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI, false);
+
 	if (tb_enable_tmu(sw))
 		tb_sw_warn(sw, "failed to restore TMU configuration\n");